降低样品采集制备过程中土壤硝态氮和铵态氮测定误差的方法

Review on the Method for Reducing Measurement Error of Soil Nitrate Nitrogen and Ammonium Nitrogen during Sample Collection and Preparation

【目的】分析新鲜土壤样品采集、保存、浸提以及浸提液存放等处置方式对土壤硝态氮、铵态氮测定结果误差的影响,研究降低测定结果误差的途径,提出实现测定结果在误差范围内的土样采集和制备方法。【方法】通过对文献收集、整理和统计分析,分析测定过程中人为影响痕迹最多的新鲜土样的采集、保存、浸提以及浸提液存放等环节的处置方式对土壤硝态氮、铵态氮测定结果误差的影响。【结果】实验室测定步骤有严格误差控制,而土壤样品采集和制备环节易引起测定数据误差;土样采集和运输时放置在室外或低温运输都会引起土壤硝态氮和铵态氮含量增加;土样风干、烘干保存时硝态氮和铵态氮含量增加,长时间冷藏含量也会增加,冷冻保存时含量变化最小;不同浸提剂和不同浸提时间的测定结果有差异,浸提液保存方式对测定结果有明显影响。【结论】测定得到接近土样采集时的田间新鲜土壤中氮含量的关键途径为加快采样速度、样品储运、浸提等环节。

【Objective】To analyze the effects of the disposal methods of fresh soil sample collection,preservation,extraction and storage of extract on the error of soil nitrate nitrogen and ammonium nitrogen determination results,and explore the ways to reduce errors in measurement results.【Methods】Through literature collection,sorting and statistical analysis,the effects of methods of collection,preservation,extraction and storage of leaching liquid on the error of soil nitrate and ammonium nitrogen determination results were comprehensively analyzed.【Results】It was so easy to cause the measurement data error that the laboratory measurement procedure had strict error control,and the soil sample collection and preparation link.When soil samples were collected and transported outdoors or at low temperature,the contents of nitrate and ammonium nitrogen in soil would increase.When soil samples were dried by wind or by heat and preserved,the content of nitrate nitrogen and ammonium nitrogen increased.The contents of them by cold storage for a long time would increase,but the change was the least,and the determination results of different extractants and different extraction time would be different,and the way of extraction solution preservation would have a significant effect on the results.【Conclusion】The key way to determine the nitrogen content in the fresh soil is to accelerate the sampling speed,sample storage and transportation,extraction and so on.In addition,the method of collecting and preparing soil samples within the error range was also proposed.